基 于 红 外 热 成 像 的 钢 管 混 凝 土 脱 空 缺 陷 检 测 研 究

During the construction of concrete-filled steel tubular （CFST） members，the internal defects are caused by improper operation and shrinkage of concrete. Among them，the gap defect will weaken the interaction between steel tube and concrete，resulting in the decline of the bearing capacity of members. Therefore，it is necessary to strengthen the detection of the gap defect of CFST members. In this paper，a detection method based on infrared thermal imaging is proposed. Relevant theoretical studies show that when the structure is defective or damaged，the thermal physical characteristics of the part will change，which is reflected in the local temperature anomaly on the surface of the object. Infrared thermal imaging method was used to experimentally detect the gap defects of CFST member. The results show that the method can effectively detect the gap defects of CFST members. The detection indexes are as follows：the temperature difference after member heating is 3 ℃ and the cooling rate ratio is greater than 1.1 in the monitoring range.